The late King Hussein of Jordan wanted Israel to bomb Syrian forces during the Black September crisis of 1970, according to British Government documents released on Monday.

The documents, disclosed under the British Government's 30-year rule and featuring in a special BBC New Year's Day documentary, reveal the king feared that the Middle East would slide into all-out war if Jordan fell into the hands of Syrian-backed Palestinian guerrillas.

That fear, at the height of an international hijacking and hostage crisis which came to define a decade of terrorism, led the King to approach the British Government and ask it to persuade Israel to intervene.

Syria was backing Palestinian guerrillas who were taking over parts of Jordan - until the Jordanian army destroyed their bases in what became known as their "Black September".

Roots of crisis

The crisis began when Palestinian guerrillas hijacked four aircraft - a fifth attempt failed - and took three of them to a remote desert airstrip in Jordan, Dawson's Field.

One of their commanders, Leila Khaled, was being held in London after the failed attempt to take an El Al flight.

King Hussein: Feared he would fall

Demanding her release, they blew up the three airliners - though released almost all the hostages amid behind-the-scenes negotiations with the UK and other governments.

However, according to the documents, the UK realised that its decision to give in to demands to release Khaled could exacerbate King Hussein's already fragile position in his own country.

If the UK, Jordan's oldest ally, was seen as siding with the Palestinians in Jordan, it could lead to the fall of the entire country into their hands.

Palestinian guerrillas, orignally allowed into Jordan by King Hussein, were already taking over areas of the country and there were fears that radicals could force the toppling of the king.

Hussein decided to fight back against the Popular Front for the Liberation of Palestine, led by a faction headed by the emerging Yasser Arafat.

But Syrian forces were already entering Jordan in support of the Palestinians.

'Extreme anxiety'

On 21 September, the British cabinet heard of King Hussein's plea for help.

According to the minutes released on Monday for the first time, the Cabinet was told that: "A series of messages has been received from King Hussein, reflecting the extreme anxiety with which he now regarded the situation.

"The clearest of these had not only appealed for the moral and diplomatic support of the United Kingdom and the United States coupled with a threat of international action, but had also asked for an air strike by Israel against the Syrian troops."

Golda Meir: Received King Hussein's message

The appeal arrived in London after King Hussein's normal channels of communication with both Washington and the Israeli Government had been cut, the documents reveal.

The documents reveal that the Cabinet Secretary, Sir Burke Trend, gained agreement from ministers to pass the message only to the US and not to Israel directly.

The US later confirmed to London that it had passed the substance of the appeal, which it had now received, to Israel's Prime Minister, Golda Meir, who was at that time in New York.

The British Government, led by then Prime Minister Edward Heath, doubted whether there were "any advantages to be derived from prolonging, possibly only for a short time, the increasingly precarious regime of King Hussein" - effectively conceding that it needed to keep its options open should the Palestinians take control.

Press reports of the Hussein appeal were vehemently denied at the time.

While Israel did not intervene, Palestinians alleged at the time that it may have supplied arms to Jordan in an effort to destroy the guerrilla bases, a growing threat to its stability.

For the full secret history of the UK's involvement in Black September - and exclusive interviews - go to our special report, UK Confidential.